Deep Brain Stimulation and Swimming Performance: A Randomized Within-person Crossover Study

Abstract

Abstract: Objective: To determine whether deep brain stimulation (DBS) causes swimming impairment, we systematically compared swimming ability between DBS on vs. off, in eighteen patients. Methods: We conducted a randomized, blinded crossover study, comparing swimming ability between DBS on vs. off, within participants. Participants swam 3 laps of front crawl and 3 laps of breaststroke. Pre-specifed primary outcomes were proportion of lap completed, lap time, and Aquatic Skills Proficiency Assessment (ASPA) score. Pre-specified secondary outcomes were a qualitative description of marked changes observed. Results: Eighteen participants with Parkinson’s disease (n=13), essential tremor (n=3), Tourette’s syndrome (n=1) or post-traumatic brain injury proximal tremor (n=1), treated with posterior subthalamic area (n=15) or globus pallidus interna (n=3) DBS were assessed. There was no significant effect of DBS on/off status on any outcome measure, for front crawl or breaststroke. Three participants showed changes in both qualitative and quantitative assessments. Of these, one participant displayed reduction in swimming ability: impairment in all outcomes with DBS on, normalizing with DBS off (the same individual as previously reported). The participant displayed difficulty coordinating limb movement as well as postural control. Two participants showed improvements in lap time and ASPA scores with DBS on. Conclusion: Overall DBS did not impair swimming performance, although one patient demonstrated a stimulation-induced drowning hazard. There were no anatomical or clinical features unique to the individual with swimming impairment. Patients should be warned about the possibility of DBS-induced drowning hazard, and should swim with capable supervision after DBS. Classification of evidence: This study provides Class IV evidence that for patients with implanted DBS electrodes, the stimulation on condition, compared to stimulation off, did not significantly impair swimming performance. A formal assessment of unblinding would have been helpful.